You see unleashed hex
Notes
It may appear during the fight against King Zelos of the Grave Danger Quest.
Abilities
Melee (?)Damage Taken From Elements
Physical 
Death 
Holy 
Ice
Fire
Energy
Earth
Location
Behaviour
Fights in close combat. Unleashed hex never retreats.
Strategy
The best strategy is probably to avoid making it spawn by not stepping on the vortex while affected by Greater Hex.